Description: FORT HUACHUCA , Ariz Airman 1st Class Jason Johnston signals team members to freeze upon sighting enemy vehicles during a tactics training exercise Oct 13 Members of the U S Air Forces in Europe Defender Challenge team are spending three weeks here in preparation for the 2004 Defender Challenge competition Defender Challenge held at Lackland Air Force Base , Texas , is a security forces competition pitting competitors from major commands against one another over a series of events including marksmanship , tactics and physical fitness Airman Johnston is assigned to the 48th Security Forces Squadron , Royal Air Force Lakenheath , England